Substitutions of praseodymium and silicon for calcium and phosphorus in hydroxyapatite structure

Substituted hydroxyapatite samples of composition Ca_10?x Pr _x (PO₄)_6?x (SiO₄) _x (OH)₂, where x = 0?6, were studied using X-ray diffraction and IR spectroscopy. Calcium substitutions occurred over the entire range of compositions studied. The crystal structure of solid solutions was refined by the Rietveld technique.     

Plasmon–phonon contribution in the permittivity of ZnP2 single crystals in FIR at low temperatures

The permittivity model for ZnP₂ crystals has been determined by reflectance measurements in the far infrared region. The dielectric permittivity is presented in the framework of the Drude–Lorentz model containing both plasmon and phonon contributions for two polarizations of incident light (E||c and Ec) at different temperatures. The temperature dependence of the oscillator parameters has been determined as well.     

Surface plasmon-phonon polaritons of hexagonal zinc oxide

The anisotropy of surface plasmon-phonon polaritons of the first and second types in hexagonal zinc oxide is investigated at various electron concentrations and orientations of the C axis of the crystal relative to its surface. It is shown that surface plasmon-phonon polaritons of a third type are generated when the electron concentration in ZnO is greater than 2×10¹⁸ cm⁻³ and the orientation corresponds to K⊥C and xy⊥C. The spectrum of the surface plasmon-phonon polaritons of the third type are calculated, and the conditions for the existence of surface plasmon-phonon polaritons of the third type in ZnO single crystals are determined. Zh. Tekh. Fiz. 68, 58–62 (January 1998)     

IR and <Superscript>31</Superscript>P NMR spectroscopic study of complexation of carbamoyl methyl phosphinates with U<Superscript>VI</Superscript> and Th<Superscript>IV</Superscript> in nitric acid solutions

The composition of complexes formed upon the extraction of U^VI and Th^IV nitrates with O-n-nonyl(N,N-dibutylcarbamoylmethyl) methyl phosphinate (L) from solutions of nitric acid without additional solvent was determined by ³¹P NMR spectroscopy. The structures of the complexes formed were studied by IR spectroscopy. Uranium(VI) is extracted from 3 and 5 M solutions of HNO₃ as the [UO₂(L)₂(NO₃)₂] complex, while thorium(IV) is extracted from 5 M HNO₃ as the [Th(L)₃(NO₃)₃]⁺·NO ₃ ⁻ complex. In both cases, ligand L has bidentate coordination. Ligand L contacts with 3 and 5 M nitric acid to form adducts L·HNO₃ and L· (HNO₃)₂, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2460–2464, November, 2005.     

Wave fluctuations in the system with some Yang-Mills condensates

Self-consistent dynamics of non-homogeneous fluctuations and homogeneous and isotropic condensate of Yang–Mills fields was investigated in zero, linear and quasilinear approximations over the wave modes in the framework of N = 4 supersymmetric model in Hamilton gauge in quasiclassical theory. The models with SU(2), SU(3) and SU(4) gauge groups were considered. Particle production effect and effect of generation of longitudinal oscillations were obtained.